In the context of the overall purpose of patent policy - to induce invention that would not otherwise occur and which delivers a net benefit to society - this paper reviews the evidence available on the question of gene patenting. The paper starts with assessing the evidence for the need for a patent system, considers who are the major beneficiaries of the patent system and reviews the extent of judicial law-making on patent policy. In Australia the extension of the patent system to “isolated and purified” materials identical to those found in nature (gene patents) is shown to be based on two decisions both made by senior public servants, from a legal not an economic perspective. The paper concludes with a consideration of the impact of patent monopolies on health care costs and availabilities. There is no independent evidence that patent monopolies are needed in this area. Many institutions and companies have been working in biotechnology since the 1980s and earlier. There was no expectation at that time that legislated monopolies would be granted.